Total Dissolved Solids (TDS) are the total weight of all solids — minerals, salts, and metals — dissolved in a given volume of water. A TDS meter measures the concentration of these dissolved inorganic substances, expressed in parts per million (ppm). The higher the TDS level, the greater the probability of contaminants in your water.
This TDS meter can be used to:
- Check the performance of your water filter or water purifier
- Test for water hardness (1 grain = 17 ppm)
- Monitor the quality of your drinking water
- Monitor pools, spas, aquariums, and hydroponics
💧 Taking TDS Measurements
- Remove the protective cap.
- Press the On/Off button to turn the TDS meter on.
- Submerge the end of the meter into the water/solution no higher than the end of the ridged plastic — about 1″ is plenty. Do not submerge the entire meter, and never dip beyond the maximum immersion level (approx. 1.5″). The unit is not water-tight and will be damaged if water enters it.
- Lightly stir the meter to dislodge any air bubbles.
- Wait until the display stabilizes (approx. 10 seconds), then press the HOLD button to view the reading out of the water.
- If the meter displays a flashing "x10" symbol, multiply the reading by 10.
- After use, shake off any excess water from the meter and replace the cap.
🌡️ Taking Temperature Measurements
- Once the meter is on, the temperature function can be used at any time, in or out of liquid.
- Press the TEMP button. The display will switch to temperature in Celsius. Press again to switch to Fahrenheit.
- To return to TDS mode, press the TEMP button again.
🔋 Changing the Batteries
- Remove the battery compartment by pulling off the top cap.
- Install new batteries (2x LR44 1.5V button cells), making sure they are properly aligned.
- Replace the battery compartment. The meter will turn on automatically.
📊 Typical TDS Readings Across Different Water Types
Drinking Water Standards
| Excellent Quality | 0–50 ppm — Distilled, reverse osmosis, and deionized water typically fall in this range. Pure, but may lack beneficial minerals and can taste flat. |
| Good Quality | 50–150 ppm — Most bottled waters and well-treated municipal supplies. Good taste while maintaining low dissolved solids. |
| Fair Quality | 150–300 ppm — Acceptable for drinking under EPA standards. May have a slightly mineral taste but is generally safe. |
| Poor Quality | 300–500 ppm — Still within EPA guidelines but approaching the upper limit. May taste noticeably mineral-heavy or slightly brackish. |
| Unacceptable | 500+ ppm — Exceeds EPA recommendations for drinking water. May cause digestive issues and has an unpleasant taste. |
Specific Water Types
| Tap Water | 50–400 ppm, varying significantly by region and treatment methods |
| Well Water | 100–1,000+ ppm, depending on local geology and mineral content |
| Bottled Water | 50–200 ppm, with spring water generally higher than purified water |
| Pool Water | Maintained around 250–400 ppm for proper chemical balance |
| Aquarium Water | Freshwater tanks: 150–300 ppm; saltwater tanks can reach 35,000+ ppm |
⚠️ Important Considerations When Using a TDS Meter
⚠️ Important: TDS meters measure total dissolved solids but don't identify specific contaminants. High TDS doesn't necessarily indicate harmful substances, as it includes beneficial minerals like calcium and magnesium. Conversely, low TDS doesn't guarantee water safety — it won't detect bacteria, viruses, or certain chemicals that don't significantly affect conductivity.
Regular TDS monitoring is valuable for tracking water quality changes over time and determining when filtration systems need maintenance or replacement.
🏪 Where to Buy the TDS Total Dissolved Solids Meter
Buy the TDS Total Dissolved Solids Meter →
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This guide is provided by Envistia Mall for educational and technical reference purposes. The manufacturer and Envistia LLC (dba Envistia Mall) are not responsible for any damages or losses resulting from the use of this product. Always follow proper electrical safety practices when working with electronic components and never exceed the meter's rated input limits. Specifications are based on manufacturer data and physical inspection of the product and may vary between production batches.